Spraying mechanism



` June2o,195o l; B. GQ'DA 2,512,542l

SPRAYING MECHANISM Filed Nov. e, 1947 Z4 l [g3 Patented June 20, 1950 UNITED ASTATES PATENT OFFlCE Iication November rsil No. '184,370l

Claims.

l My invention relates to spray devices and more in particular to a device for controlling the spray from the'` usual spray gun employed in painting and the like. I

In my prior application, which issued as Patent No. 2,440,084, on April 20, 1948, I disclosed a spraydevice particularly adapted for lithographic work. In such spray device, I provided a cone withan aperture at its tip so constructed and arranged that the proportion of spray passing the orice could be controlled and the remaining portion re'iiirned to the paint reservoir. I'was also able tocontroi the character oi' the spray passing the orifice to obtain the diierent effects desired, in lithographic work. I have now found that by further development of the orice arrangement, and particularly by the provision of a plurality of orifices having a particular relatlonshipto the spray, I am able to produce a very sharp line for striping and similar work and at the same time control very accurately the amount and disposition ofthe paint as applied over the sprayed surface.` Heretofore, methods proposed for producing a sharp edged stripe have been unsatisfactory when such methods depended upon control of the spray by the spray device itself. So far as I know the only commercially successful means for striping is by use of masking tape and the like, and the problem of controlling the eiiluent is such that attempts to reuse masking devices, as by the use of stencils and the like, have not been successful where it was necessary to produce a finished result without blotting.

The principal object of my invention is the provision of an improved spray device and method for controlling the spray such as discussed hereinabove.

In the drawing, I show a preferred embodiment of the invention in which- Fig. l is a, fragmentary elevational view partly in section showing the control mechanism associated with the spray gun and reservoir for paint;

Fig. 2 is A,an elevational view looking at the left hand side of Fig. l;

Fig. 3 is a slightly enlarged vertical sectional view taken 4on the line 3-3 of Fig. 2;

Fig.'4 is a fragmentary sectional view taken on lthe line 4--4 of Fig. 3; and

Fig.5 is a perspective view of a masking hou`s ing forming a part of the device.

-Referring now to the drawings, I show a conventional type of spray 'gun `ll which, by means of suitably controlled air connections, withdraws paint from a reservoir H through a pipe I2 and delivers it in spray form admixed with air through a nozzle I 3. The device heretofore described is of usual conventional form and may take various forms, all well known in the spray lndustry. Supported in front of the nozzle I3, I provide a spray control devicevindicated generally by the reierence character I4 which spray control device may take various forms providing the essential characteristics described hereinbelow are maintained. d

In the form shown, I secure to a cover I6 of the ,reservoir a square pipe I'I having a discharge outlet Il to the reservoir Il. Telescoped within the square pipe I1 is a square elbow I9, a screw 2i being provided to releasably secure it within the square pipe i1. A hollow shell 22 has a hollow mounting stem 23 which extends into the upstanding open end of the elbw I9 and is held in position by screw 24. The spray controlling mechanism is housed within the'hollow shell'22.

Screwed within a threaded boss 26 on that wall of the shell opposite the nozzle. and also opposite a. relatively wide opening 21 is a generally conical shell having an apex orlce 29.

The apex orifice 29 is aligned with the center of the spray from the nozzle Il so that a portion of that spray passes the apex orice 29 and a portion strikes the outside of the generally conical shell 28 and is thus prevented from passing through the orifice. It will thus be seen that I use the term "conicaP inta .general sense to delinea construction which can have the desired effect, and such structure may have flat, rounded, hyperbolic, or circular sides, providing they diverge from the orifice. I may, therefore, yrefer to this portion of the device as a diverging centrally apertured separator which may have orifices of various sizes as will be made clear when the operation of the device is explained. Such portionl of the spray as does not pass the orifice 29 flows byg'ravity'through the hollow mounting stem 2l and thence to the reservoir Il. lThere is a tendency for some of the spray to accumulate on the inside of the generally conical member .28 and this portion is delivered to the hollow shell and thence to the reservoir through the drain 3|.

In front of the ldiverging separator, the boss asians erally conical portion 3l in the nature ofa diverging 'spray'separaton the function of which will be described later., 'I'he exterior open side of the masking housing has horizontal side guards 3l. theseguards being spaced a distance approximately equal to the diameter of the spray -at this point. The masking housing is slightly recessed as shown so that any slight amount o! paint which may accumulate on the inside thereof will be prevented from discharging as a solid body, Itherebyproducing a blob or blot and marring the uniformity of the sprayed surface.

The important problem in control of a spray is to maintain a uniform distribution of the spray substantially regardless of the length of time that the device is in operation. I have found that this involves control of air currents and preventingrgradual accumulation of paint at points where unintended dislodgment and discharge can take place. It will beA noted that the orifice 29 is almost at the exterior of the opening 21 in the shell and the parts are so positioned that a swirling of air will not occur but the paint will be' carried aawy from the orifice 29 at the exterior of the diverging separator, and the air from which the paint has been removed easily passes v out of the relativelylarge opening 21. Ports 31 at the opposite side of the diverging separator permit the release of such pressure as may tend to build up between the orifices 29 and 3l, and

the air which escapes here is also free of paint.

This freedom of paint is in part brought about by the introduction of a screen 3l which picks' up any stray paint particles.

In using the sdevice of my invention, the side guards 35 may be placed very close to or against a surface to be striped, and to control the straightness of the line desired, I provide a guard such as shown. A square channel 39 has a slider 6i into the front and end of which guide elements I2 and I3 are screwed. A fastening nut Il will retain the sliderV 4i in any position to which it is adjusted. Thus the guide elements 42 and I3 may be extended, retracted, or, in short, brought to any front or side position, respectively, which may be essential to following a guide such as a straight edge, a wall, a window sill, or any protuberance which can be used to position a. stripe. The orifice 29, orice 34 and guards 38 are all predetermined in accordance with the width" of the spray desired. They are so dimensioned that they frame approximately the outside of the normal cone-shaped spray and are so positioned that they will remove the outside eddying portion of the spray. To produce a half-inch stripe, for example, theguides 36 are it Vinch apart, the orifice 34 is 1% inch in diameter and the orifice 2! is approximately inch in diameter. These figures are illustrative of dimensions required when the longitudinal spacing is approximately that shown in the drawing. When a larger or smaller stripe is desired, both the member 2l and the member 32 are removed and replaced with members having orifices -of the dimensions required. I have, for example, used an orifice as small as 1,52 inch at 29 for a small stripe as well as oriilces of 11g inch and 11g inch. The orifices 3l and 32 are correspondingly modied as explained. While I- have shown the members 32 and 28 as separate parts, those skilled in the art will understand that this is for convenience in manufacture, and, of course, it would be possible to'have a single part so that the relationship of the orifices to each other is maintained.

Assuming that it has been determined what sise line is wanted and the device hasbeen set up ready for operation, it is only necessary to pperate the spray gun and move the guards 2| parallel to' the line being drawn. It is, of course, not essential that these guards be parallel but I have found that this is a convenience in operation and removes the last possibility, because o! slightly faulty adjustment or. the interposition of factors which cannot be accounted for, of depositing traces o! spray outside the margin of the intended line. Buch slight amountof paint as may be removed from the side of the spray at this point will be trapped on the inside of the masking housing and can be removed suitably with a cloth. Generally, however, long operation is possible. without the need of cleaning. What I claim as new and desire to protect by Letters Patent of the United States is:

1. The combination comprisinga spray nozzle, 2o a hollow shell supported in front of the spray nozzle, the shell being substantially closed except for openings provided along the path of the spray, an apertured spray diverging device within the shell with its said aperture adjacent the exterior of the shell, a masking housing supported in said shell opening furtherest removed from the spray nozzle, said masking housing having v device within the shell with its said aperture ladjacent the exterior of the shell, a masking housing supportedin said shell opening furtherest removed from the spray nozzle, said masking 40 housing having a cone-like portion projecting toward the spray with an oriilce larger than the first-mentioned orifice, and a pair of parallel side guards carried by the housing and spaced a greater distance from each other than the diameter of the second-mentioned orifice, said side guards positioned to engage a work surface and define the limits of astripe.

3. The combination comprising a spray nozzle,

a hollow shell supported infront of the spray nozzle, the shell being substantially closedexcept for openings provided along the path of the spray, an apertured diverging spray separating device within the shell with its said aperture adjacent the exteriorof the shell, and a masking housing supported in said shell opening furtherest removed from the spray nozzle, said masking housing having a cone-like portion projecting toward the spray with an oriiice larger than the first-mentioned orifice, said separating 6o device having side ports for passing air and preventing building up of air pressure in the shell and between the said orifices.

4. A spray device particularly adapted for striping, comprising in combination, a spiray nozzle, a shell support having an opening 'adjacent the said spray nozzle, a conical shell supported in said shell support with its apex at said opening adjacent the spray nozzle, the said apex being apertured to pass a substantial portion of the spray in the form of a cone, and a masking housing supported lin the base portion of the conical shell with a generally conical apertured portion projecting into the shell so as to trap an outside portion ofthe spray. said conical shell 75 having a drain to pass trapped liquid to said shell spray, an apertured diverging spray separating support. and said sneu support having av bottom drain.

5. A spray device particularly adapted for striping, comprising in combination, a spray nozzle, a shell support having an opening adjacent the said spray nozzle, a conical shell supported in said shell support with its apex at said opening adjacent the spray nozzle, the said apex being apertured to pass a substantial portion of the spray in the form of a cone, a masking housing supported in the base portion of the conical shell with a generally conical apertured portion projecting into the shell so as to trap an outside portion ofthe spray, said conical shell having a drain to pass trapped liquid to said shell support, said shell support having a bottom drain, and said masking housing having an exterior aperture with at sides forming guides, each said aperture along the path of the spray being larger than its predecessor so as to trap a portion of the exterior of the spray, and i'orm a 5 sharp outline between said guides.

LAWRENCE B. copa.

REFERENCES CITED rIhe following references are oi' record'in the l0 le of this patent:

UNITED STATES PATENTS 

